Wire strapping tool



Nov. 8, 1966 P. F. BOOMGAARD 3,234,011

WIRE STRAPPING T001;

Filed May 11, 1964 2 Sheets-Sheet 1 INVENTOR. PETER F BOOMGAARD A TORNE Y I 3, 1966 P. F. BOOMGAARD Q 3,

WIRE STRAPIING TOOL 2 Sheets-Sheet 2 Filed May 11, 1964 United States Patent 3,284,011 WERE STRAPPING TOOL Peter F. Boomgaard, Spring Lake Township, Ottawa County, Mich, assignor to Gardner-Denver Company, a corporation of Delaware Filed May 11, 1964, Ser. No. 366,465 3 Claims. (Cl. 242-7) This invention pertains generally to a tool for wrapping a wire about a terminal to provide an electrical connection and, more particularly, to a tool for connecting a plurality of spaced electrical terminals by means of a continuous length of wire.

Wrapping tools intended for electrically interconnecting spaced terminals by means of a single bare wire are commonly denominated wire strapping tools; and, such tools differ in construction and operation from wrapping tools of the more conventoinal type described in United States Patent 3,078,052 in the manner in which wire is supplied to the wire wrapping bit. Thus, in conventional wire wrapping tools, the wire to be wrapped is inserted into the forward or free end of the bit while in wire strapping tools the wire usually passes through the tool itself and into that end of the bit which is attached in driving relation with the drive mechanism of the too-l. The entry of the wire at the rear end of the bit has, in the past, created special problems in the design and arrangement of the operating mechanism of wire strapping tools with the result that available tools of this type are inherently mechanically complex and display many undesirable characteristics such as high initial cost, low operational reliability and high maintenance requirements. Therefore, a broad object of this invention is to provide a wire strapping tool of simplified construction which is characterized by low cost of manufacture and maintenance and by ease and efiiciency in operation.

Another object is to provide a wire strapping tool which is simply constructed yet has provision for external adjustments of its internal operating mechanism which provide flexibility and ready adaptability to changes in tool application.

Yet another object is to provide a wire strapping tool provided with adjusting means for the operating mechanism thereof for controlling the number of turns of wire applied to a terminal during each wrapping operation.

Still another object is to provide a wire strapping tool provided with adjusting means for the operating mechanism thereof for adjustably establishing an indexed angular position for the wrapping bit.

A still further object is to provide a pressure fiuid actuated wire strapping tool having fluid-regulating means for controlling the rotational speed of the wrapping bit.

For the attainment of the above generally stated objects and more detailed objects which will hereinafter appear, the invention contemplates the provision of a simple operating mechanism including a pressure fiuid actuated piston operable to reciprocate the rack element of a rack and pinion mechanism. Rotation of the pinion is coupled to the wrapping bit through a unidirectional ratchet means and the travel of the rack is adjustably limitable to establish the total rotational displacement and the arrested angular position of the wrapping bit.

In the drawings:

FIG. 1 is a longitudinal sectional view showing the tool in wrapping relation with a terminal;

FIG. 2 is a sectional view taken substantially along lines 2--2 of FIG. 1;

FIG. 3 is an enlarged View taken along lines 33 of FIG. 1;

FIG. 4 is an enlarged fragmentary sectional view taken along lines 4-4 of FIG. 1;

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FIG. 5 is an enlarged fragmentary sectional view taken along lines 55 of FIG. 2;

FIG. 6 is an enlarged fragmentary view taken along lines 66 of FIG. 1; and

FIG. 7 is an enlarged fragmentary perspective view of the bit shown in FIG. 1.

The embodiment of the invention shown in the drawings includes a plural part housing comprising a main housing member 10, having a hollow depending handle portion 12, a handle closure cap 14, and a rear closure member 16. The three parts of the housing are held in assembled relation by means of screws, not shown, and may be disassembled to provide easy access to the internal operating parts of the tool. The forwardly projecting nose portion 18 of the main housing member 10 has a stepped longitudinal bore 20 which receives and retains therein in fixed relation a generally cylindrical collet 22 which in turn receives the rear end of a bit sleeve 24. The sleeve 24 rotatably journals a wire wrapping bit 26 and is held in assembled relation with the collet 22 by means of a collet nut 28. The rear closure member 16 is provided with a stepped bore 30 which is axially aligned with the bore 20 and has a Wire guide bushing 32 pressed into the rearward opening thereof.

A spindle 34 is rotatably supported within the tool housing by means of a bearing assembly 36 seated in bore 20 and a bearing assembly 38 seated in bore 30. An enlarged portion 40 of spindle 34 extends forwardly beyond the bearing assembly 36 into a bushing 42; and, the extreme forward end of spindle 34 is provided with a stepped surface, not shown, which engages a complementary stepped surface 44 on the enlarged rear end of the bit 26. It will be understood that the interfiitting engagement of these stepped surfaces within the confines of the surrounding bushing 42 provides a tang driving connection between the spindle 34 and the bit 26. The spindle is provided with a longitudinal bore 46 which is in alignment with a radially opening wire-receiving groove 48 in the bit 26 and with a central aperture 50 through the wire guide bushing 32.

The driving means for the spindle 34 and the spindledriven wire wrapping bit 26 generally comprises a pressure fluid-actuated rack and pinion mechanism. A rack 52 is formed at one side of a piston rod 54 which extends upwardly from a pressure fluid-actuated piston 56 which is reciprocable within a cylinder 58 defined in the handle portion 12 of the main housing member 10. A pinion gear 60 is integral with a pinion shaft 62 which has its opposite ends journaled by bearing assemblies 64 and 66, respectively. As shown in FIG. 5, the rod 54 is generally T-shaped in cross section and during longitudinal reciprocation guidingly interfits with a T-shaped opening 68 in a plate 70 seated in the upper end of the cylinder 58. A coiled return spring 72 is held in compression between the piston 56 and the guide plate 79 and exerts a continuous downward bias on the piston 56 which urges the same to its lower limiting position. A threaded stop member 74- which is received in a threaded aperture 76 in closure member 16 interferingly coacts with one of four longitudinally spaced abutments 78a-d relieved on the rod 54 opposite the rack 52 to limit the downward travel of the piston 56. As will be more fully explained, the stop member 74 may be externally adjusted to vary selectively the length of the pistons downward stroke.

The piston 56 is forced upwardly in cylinder 58 against the bias of return spning 72 by compressed air, or an equivalent pressure fluid, which is supplied to the lower end of the cylinder in response to depression of an operator controlled trigger 80 extending forwardly from the handle 12. To this end, compressed air is communicated to a supply chamber 82 through a. service conduit 84 and a connecting passage 86 in the handle closure cap 14. The upper end of the air supply chamber 82 is normally closed by an O-ring 88 carried at the lower end of an actuating rod 90. The rod 90 is normally biased to the position shown in FIG. 1 by a coiled return spring 92 and is shift-able downwardly against the bias of spring 92 by the action of a cam surface 94 overriding the upper end of the rod 90 in response to depression of the trigger 80 and "an attached pin 96. A neck portion 98 of rod 90 coacts with a vertical bore 100 which houses the rod 90 to define an annular chamber 102 which functions to connect the cylinder 58 to atmosphere when the trigger 80 is released and to the air supply chamber 82 when the trigger is depressed to actuate the tool. As shown in FIG. 1, an inclined bleed passage 104 normally coacts with the annular chamber 100 to vent air from below the piston 56 to atmosphere. As the rod 90 is cammed downwardly, the upper opening of the bleed passage 104 to chamber 102 is closed and the O-ring 88- unseats to permit motive air to enter the cylinder 56 through the chamber 102 and the lower portion of the bleed passage 104.

When motive air is introduced below the piston 56, in the manner described above, the piston will be forced upwardly carrying the piston rod 54 upwardly through the guide plate 70 and compressing the return spring '72. At the same time, the teeth of the rack 52 will mesh with the pinion 60 causing the pinion shaft 62 to rotate counterclockwise .as viewed in FIGS. 2 and 6. The upper limit of the travel piston 56 and rod 54, as shown in phantom lines in FIG. 1, is defined by the engagement of the extreme upper end of the rod 54 with an adjustable abutmen-t provided by a threaded stop member 106 extending through the top of the main housing member 10. The speed of upward travel of the piston 56 and hence the speed of rotation of the bit 26, as will be hereinafter explained, is controllable by a regulating screw 108 which may be advanced and retracted within a complementary opening in the handle closure cap 14 to vary the cross A speed reduction gear 110 is journaled on and is freely rotatable about the pinion shaft 62 forwardly of the pinion gear 60. When the pinion 60 is rotated by the upward movement of the rack 52, the gear 110 is driven counterclockwise by means of driving engagement be tween a ratchet wheel 112 formed integrally with the pinion shaft 62 and a spring biased drive pawl 114 pivotally attached to the rear face of the reducing gear 110. As shown in FIG. 6, a leaf spring 116, which is positioned and held by a pair of pins 118 and 120 projecting from the rear face of the gear 110, urges the drive pawl 114 into interfering engagement with one of the five teeth of the ratchet wheel 112. To complete the driving connection between the air-actuated piston 56 and the wrapping bit 28, the reducing gear 110 meshes with a pinion gear 122 integrally formed intermediate the ends of the aforementioned spindle 34 to rotate the spindle and the wrapping bit 26 in a clockwise direction. An indexing pawl 124 is pivotally mounted in a cavity 126 laterally offset from the periphery of the reducing gear 110, as best seen in FIG. 6; and, the pawl 124 is biased by a pawl spring 128 into engagement with the teeth of the reducing gear to arrest clockwise rotation of the same.

In describing the wrapping operation of the tool it will be convenient to assume that the tool has been applied to a terminal 130 projecting from a panel 132, as shown in FIG. 1; and, reference to the direction of rotation of the various parts will be made as the tool is viewed in FIGS. 2 and 6. The terminal 130 is positioned in a terminalreoeiving bore 134 opening to the end face 136 of the bit 26; and, a bare Wire 138 extends completely through sectional area of the aforementioned motive air passage the tool through the aperture 50 in the wire guide bushing 32, the longitudinal bore 46 of the spindle 34 and the wire-receiving groove 48 of the bit 26. As illustrated in FIG. 1, the wire 138 has been Wrapped around the uppermost terminal 140 and around another terminal 142 just below it to strap or interconnect these terminals with a continuous length of wire. After completion of each wrap, the tool is moved to another terminal causing the wire to be drawn through the aligned openings in the tool. The wire may be continuously supplied to the rear of the tool from any source such as a reel or spool.

After positioning the tool as shown in FIG. 1, the trigger is manually depressed against the bias of return spring 92 to admit motive air below the piston 58 which will then travel upwardly as the air expands beneath it to its upper limiting position established by the adjust-a- 'ble stop member 106. As the rack 52 travels upwardly in driving engagement with the pinion gear 60, the pinion shaft 62 and ratchet wheel 112 rotate counterlcockwise. The engagement of the teeth of the ratchet wheel with the pawl 114 imparts counterclockwise rotation to the reduction gear which, in turn, meshes with the spindle gear to rotate the spindle 34 clockwise; and, the spindle drives the bit for clockwise rotation with respect to the stationary sleeve 24 and terminal 130. Such rotation of the bit 26 with respect to the terminal will cause the wire to be drawn through the wire-receiving groove 48 and wound tightly about the terminal in helical convolut-ions as seen in the completed connections 144 and 146. Reference may be had to US. Patent 3,078,052 for the details of a preferred configuration of the bit face 136. After wrapping rotation of the bit is arrested by the abutment of the piston rod 54 and the stop screw 106, the trigger 80 may be released thereby interrupting the flow of air from supply chamber 82 and venting the cylinder 58 and permitting the return spring 72 to force the piston 56 rapidly downwardly to its lower limiting position, shown in FIGS. 1 and 2, which is defined by the interference of the stop member 74 with the stepped abutment 73b. A feature of the present invention is the provision of a unidirectional drive mechanism connecting the driving pinion shaft 62 to the driven spindle 34 thereby avoiding retrograde or unwrapping rotation of the bit as the pinion shaft is rotated in a clockwise direction upon deenerg-ization of the tool. To this end, the indexing pawl 124 is spring biased into arresting engagement with a tooth of the reduction gear 110, as shown in FIG. 6,

to restrain clockwise rotation of the gear 110 and counterclockwise rotation of the spindle pinion gear 122. At the same time, however, the ratchet wheel 112 and the pinion shaft 62 are free to rotate in a clockwise or retrograde direction with respect to the drive pawl 114 which overrides but does not engage with the teeth of the ratchet wheel.

According to the present invention the tool is provided with a working mechanism which can be adjusted to meet changing requirements of a given wiring application and to accommodate widely diversified applications of this type of tool. The length of return stroke of the piston 56 may be adjustably limited and varied by external adjustment of the threaded stop member 74 to coact with a selected one of the stepped abutments 78ad shown in FIG. 2. By regulating the length of stroke of the piston 56, the total angular displacement of the bit 26 during each wrapping cycle, hence the number of wraps applied to a termina, may be selectively determined. In the illustrative embodiment of the invention shown in the drawings, the abutments 78a-d are vertically spaced on piston rod 54 to provide four increments of bit rotation of one comthe rotative speed of the bit 26, may be regulated in accordance with the diameter and stiffness of the wire 138 thereby asuring smooth feeding and wrapping of the wire. As the tool is moved from terminal to terminal, it may happen that the wire 138 will be drawn from the groove 48 in such a manner that the wire partially covers the terminal-receiving bore 134 thereby interfering with positioning of the bit over the next terminal. This inconvenience is advantageously avoided in the present tool by the provision of means for fixing the angular position of the groove 48 at the completion of each wrapping cycle so that the bore, the groove, and the wire are related substantially as shown in FIGS. 1 and 3. Indexing of the groove 48 in this manner is accomplished by external adjustment of the threaded stop member 106 which abuttingly coacts with the extreme upper end of the piston rod 54 to provide the upper limit of piston travel. By so adjusting upward piston travel, the final angular position of the reduction gear 110 is established and is thereafter maintained by the pawl 124, thereby determining the arrested rotational position of the spindle 34 and the bit 26 at the completion of each wrapping operation. The pawl 124 will restrain the bit against backward or unwrapping rotation thereby positioning and holding the bit groove 48 in any preadjusted home position.

From the foregoing description it will be appreciated that the operating mechanism of the present tool may be simply and rapidly adjusted to vary the number of turns of a connection, the speed of the wrapping operation and the indexed rotary position of the bit. These features of the tool provide great flexibility in its use and are essential to the ability of the tool to fulfill the requirements of speed and efiiciency imposed by users.

It will be understood that the above description and accompanying drawings comprehend only a general and preferred embodiment of the improved wire strapping tool and that various changes in construction, proportion and arrangement of the elements thereof may be made without sacrificing any of the above enumerated advantages of the invention.

Having fully described the invention, what is claimed as new and useful is:

1. A wire strapping tool comprising:

housing means;

spindle means disposed in said housing means and having a longitudinal wire passage therethrough;

wire wrapping bit means drivably connected to said spindle means and having wire-receiving means communicating with said wire passage;

rotary driving means disposed in said housing for rotating said spindle and said bit;

said driving means including a longitudinally reciprocating member cooperable with a first stop member for limiting longitudinal movement of said reciprocating member in one direction thereby to determine the total rotational displacement of said bit during each wrapping operation; and

said reciprocating member having a plurality of longitudinally spaced abutments, a selectable one of which being cooperable with said first stop member to establish different limits of longitudinal movement of said recriprocating member in said one direction.

2. The invention defined in claim 1, together with a second stop member cooperable with said reciprocating member for limiting longitudinal movement of the latter member in the other direction thereby to define an indexed angular position of said bit at the completion of each wrapping operation.

3. The invention defined in claim 2, wherein said second stop member is disposed in movable relation with said reciprocating member and is adjustable with respect to the latter member to define different indexed angular positions for said bit.

References Cited by the Examiner UNITED STATES PATENTS 2,682,063 6/1954 Miloche 242-7 X 2,793,419 5/1957 Larsen 29-33 3,108,620 10/1963 James 124 3,117,736 1/1964 Loy et a1. 2427 3,179,130 4/1964 Silins et a1. 140124 FRANK I. COHEN, Primary Examiner.

B. S. TAYLOR, Assistant Examiner. 

1. A WIRE STRAPPING TOOL COMPRISING: HOUSING MEANS; SPINDLE MEANS DISPOSED IN SAID HOUSING MEANS AND HAVING A LONGITUDINAL WIRE PASSAGE THERETHROUGH; WIRE WRAPPING BIT MEANS DRIVABLY CONNECTED TO SAID SPINDLE MEANS AND HAVING WIRE-RECEIVING MEANS COMMUNICATING WITH SAID WIRE PASSAGE; ROTARY DRIVING MEANS DISPOSED IN SAID HOUSING FOR ROTATING SAID SPINDLE AND SAID BIT; SAID DRIVING MEANS INCLUDING A LONGITUDINALLY RECIPROCATING MEMBER COOPERABLE WITH A FIRST STOP MEMBER FOIR LIMITING LONGITUDINAL MOVEMENT OF SAID RECIP- 